JPH0735238B2 - Kick mechanism of aerial work vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to the construction of a building at a high place, the work of working at a high place such as painting, and the like, lifting an operator or a material upward, Regarding an aerial work vehicle used for unloading unnecessary materials from a high position during work, in particular, a high height that can prevent cutting of wires, chains, etc. that connect each boom when the lifting platform descends. The present invention relates to a kick mechanism of a work vehicle.

[Conventional technology]

For assembling, painting, and repairing in high places such as highways and building construction, many aerial work vehicles that raise and lower the lift are used, and it is not necessary to put workers, materials, etc. on the lift and lift it. I was working on loading and unloading the materials.

In this conventional lifting device, a pantograph-shaped expansion / contraction mechanism is used in which a pair of arms are pivotally attached at the center to form one set, and a plurality of sets of arms are vertically connected (so-called scissors type). In the mechanism, in order to increase the maximum rising height of the lifting device, it is necessary to increase the length of the arms of each set or increase the number of connected arms. Therefore, when designing an elevating device that can raise the height that can be raised, a large number of sets of pantographs must be used, and the height of the elevating device when the vantagraph is folded becomes high, so that workers can get on and off the platform. However, the work of loading and unloading materials was troublesome.

In order to eliminate this drawback, various proposals have hitherto been made, and a structure as disclosed in, for example, US Pat. No. 3820631 has also been proposed. In this proposed structure, the lower boom and the upper boom, which can move linearly with respect to the middle boom, are inserted and inserted freely in the middle boom.
It is assembled so that the lower end of the lower boom is pivotally supported on the vehicle body side by a pin and the upper end of the upper boom is pivotally supported on the platform by a pin to form an X shape. In this structure, since the boom itself is long, the height of the platform can be lowered and the platform can be lifted to a high position in the folded state.

However, in this invention, lower boom than middle boom,
Since the mechanism for extending the upper boom is composed of a screw and a female screw that meshes with the screw, the expansion and contraction moving speeds of the lower boom and the upper boom relative to the middle boom are slow, so that the platform cannot be quickly responded. Also, since the lower and upper booms are slid by the bevel gears provided in the center of each middle boom, set the total length of the lower and upper booms to only half the length of the middle boom. The middle boom, the lower boom, and the upper boom could only extend half the length of the middle boom, and the platform could not be lifted higher.

Also, a structure has been proposed in which another boom is inserted into the boom and extended to extend the entire length of the boom itself. For example, in Japanese Patent Laid-Open Publication No. 119556 of 1978, in FIG. 4 of the drawing, a lower boom and an upper boom having a smaller diameter are inserted into a middle boom having a larger diameter, and the lower boom and the upper boom inserted therein are inserted. It has been proposed to extend the boom length by pulling it out from the middle boom, thereby raising the platform high.

However, in this structure, there is no mechanism that synchronizes the expansion and contraction amount between the lower boom and the upper boom that are pulled out from the middle boom, they move individually, and the expansion and contraction amount is restricted by the link mechanism by the bar. There is. For this reason, the platform cannot be lifted horizontally in the vertical direction, and cannot be lifted to a desired vertical height position. Also, when the lower and upper booms housed in the middle boom are expanded and contracted, the link mechanism formed by the bar is used to regulate the amount of movement of each, so perfect synchronization of the amount of movement is impossible. Therefore, the lower boom and the upper boom cannot be connected to the platform by a pin or the like, and the error that cannot be synchronized has to be made by the roller contacting the vehicle body and the platform. For this reason, the platform is subject to cumulative rattling due to the large number of shaft fulcrums due to the link mechanism and rolling due to the rollers as it is, so it has a structure that easily shakes and easily rocks due to wind etc. And, it made the workers feel uneasy.

In order to solve these drawbacks, for example, patent application Showa 56
No. 41289 is proposed every year. In this application, the lower boom and the upper boom are inserted into the middle boom, the ends of the lower boom and the upper boom are connected by flexible connecting means, and the connecting means is pivotally supported by the middle boom. It is a structure in which the moving direction is changed by the changing means. In this configuration, the lower boom is pulled out from the middle boom, and at the same time, the upper boom is pushed out from the middle boom and the upper boom, and the movement amount of the lower boom and the upper boom is restricted by the connecting means. The amount of movement is the same, and a pair of middle booms pivotally supported at the center of the booms can rotate in an X shape to push up the lifting platform vertically upward.

In this configuration, in order to store the lower boom and the upper boom in the middle boom, if the lower boom and the upper boom are extended from the middle boom, the total length should be extended to about three times the length of the middle boom. The lift table can be lifted high.

In such a newly proposed aerial work platform, X
The lower boom and upper boom are configured to extend and retract one by one from the upper and lower open ends of the pair of middle booms that are shaped like a letter, and the lower boom is connected to the vehicle body side, and the upper boom is connected to the lifting platform by the side surface. The feature was that the structure was such that an X-shape was formed when viewed from above. With this structure, it is possible to lower the height position when folded like a scissor type, and since the tips of the lower and upper booms are connected with pins, it is possible to firmly move up and down against shaking and the like. Can be held, and is highly safe.

Also, since the lengths of the lower and upper booms can be made approximately equal to the length of the middle boom, respectively, the lifting platform can be raised to a higher position, and the lifting height of the lifting platform can be increased compared to the total length of the folded state. There have been many merits that can be set high.

However, in the configuration of the conventional X-type aerial work vehicle, it is necessary to connect the lower boom and the upper boom in each middle boom with a wire or a chain in order to synchronize them. By connecting the upper end of the lower boom and the lower end of the upper boom with this wire, chain, etc., the moving lengths of the lower and upper booms that are pulled out from the middle boom are synchronized, and the lifting mechanism is always X-shaped. Was held. As described above, synchronizing with a wire or a chain is extremely simple in structure, but a safe load must be set for tensile stress in order to prevent a cutting accident.

This setting of the safety load did not cause much problem when the ratio of the height of the X-shaped lifting mechanism that can be lifted to the maximum height from the folded state is small. However, when the ratio of the height at which the lifting platform is lifted to the length of the lift mechanism folded is large, setting the safety load has become a very important issue.

That is, when the lifting platform is lifted to a high position, the angle at which the boom is elevated with respect to the horizontal is large, and the component force of the load applied to the lifting platform is not so large. Therefore, the tensile force applied to the wire connecting the lower boom and the upper boom does not become excessive. However, when the platform is in the lowered state, the angle of inclination of the boom with respect to the horizontal is small, and the component force of the load applied to the platform is large. The component force of this load is applied as it is to the wire and chain for synchronization, and the tensile force becomes extremely large. Therefore, if the safety factor of the load applied to the wire, the chain, etc. is set to be small, an accident will occur in which the wire, the chain, etc. are broken by the component force. If the wire, chain, etc. connecting the lower boom and the upper boom were broken, the elevator platform would suddenly descend, causing personal injury to workers on board and damaging nearby structures.

Therefore, if a wire or chain with a low safety factor is used for synchronizing the lifting mechanism, it will not be a problem when the lifting platform is lifted high, but lowering the lifting platform will increase the load component force. This was one of the causes of the accident that the elevator, the wire, the chain, etc. were cut, and the elevator was lowered suddenly.

In order to prevent the occurrence of such an accident, the safety factor should be increased and the safety load of the wire, chain, etc. should be designed large. However, if the wire, chain, etc. are made thick to increase the safety load, in extreme cases, the wire becomes too thick, and the weight increases, and the flexibility deteriorates, making it difficult for the lifting mechanism to function smoothly. Became.

[Problems to be Solved by the Invention]

In the present invention, the kick mechanism used for the initial start-up of the lifting mechanism is used, and the kick mechanism assists the load from the middle of the lowering of the lifting platform. For this reason, the load can be dispersed by the kick mechanism when the lift table is lowered and the boom tilt angle becomes shallow and the component force of the load becomes large. Therefore, even if the lifting platform descends near the lowest position and the component force becomes extremely large as it approaches infinity, the tensile force applied to the wire does not become large, and the wire, chain, etc. are relatively low in design. The kick mechanism for an aerial work vehicle that can be set to a safety factor is provided.

[Means to solve the problem]

The present invention relates to a movable vehicle body, a lift table that is located above the vehicle body and that can be moved up and down, a pair of middle booms that are pivotally supported in an X shape so as to be rotatable in the center, and the length of each middle boom. The lower boom connected to the car body at the lower ends, and the upper boom connected to the lift platform at the upper ends, which move in the length direction of each middle boom, and the lower boom connected to the car body. It consists of a kick mechanism that is fixed and pushes up the center of both middle booms, and a detection unit that detects that both middle booms and kick mechanism contact each other.The lifting platform descends and the middle boom contacts the upper end of the kick mechanism. The present invention provides a kick mechanism for an aerial work vehicle, characterized in that the kick mechanism lowers the load of the middle boom while supporting the load of the middle boom after the fact is detected by the detecting means.

[Action]

In the present invention, the detection means for detecting that the kick mechanism is in contact with the middle boom is provided, and when the raising / lowering mechanism descends from a high position and comes into contact with the kick mechanism, in the movement below the contacted height position. The kick mechanism can support the load of the lift. By distributing this load,
No load is applied to the wires, chains, etc. built into the lifting mechanism, and all of the component force generated from the load on the lifting table is not held by the wires, chains, etc. Therefore, the safety factor set for the wire, chain, etc. can be kept low. Therefore, the lower boom and the upper boom can be synchronized with each other without thickening the wire, the chain, or the like or using an excessively large mechanism.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a side view showing a state in which the elevator is lowered to the lowest position in the present embodiment, FIG. 2 is a front view of the same, and FIG. 3 is a state in which the elevator is lifted to the maximum height position. It is a side view shown.

In the figure, reference numeral 1 is a vehicle body, and front and rear wheels 2 and 3 are pivotally supported on the front, rear, left and right of the vehicle body 1, and an elevating mechanism 4 is mounted on the upper surface of the vehicle body 1. An elevating table 5 is located on the upper surface of, and a handrail 6 is fixed around the elevating table 5. A kick mechanism 7 for initial lifting of the lifting mechanism 6 is attached to the center of the upper surface of the vehicle body 1.

This elevating mechanism 6 is composed of four sets of telescopic boom bodies 10, two telescopic boom bodies 10 in a set are arranged on both left and right sides, and the telescopic boom bodies 10 of each set are a central boom 11 and a lower intermediate boom. It comprises a lower boom 13, a lower boom 13, an upper middle boom 14, and an upper boom 15.

And, out of the telescopic boom body 10 of each set of two,
The insides of the pair of central booms 11 are pivotally connected to each other in an X shape so as to be rotatable. The lower intermediate boom 12 is inserted through the lower end opening of the central boom 11 so as to be able to extend and contract in the length direction of the central boom 11.
It is inserted into the lower end opening of 12 so that it can expand and contract along its length. A connecting piece 16 is fixed to the lower end of the lower boom 13, and the connecting piece 16 is rotatably connected to a fixed piece 17 fixed to the front and rear of the vehicle body 1 by a pin.

Further, the upper intermediate booms 14 are inserted into the upper end openings of the respective central booms 11 so as to be slidable along the length direction of the central booms 11, and the upper booms 14 are inserted into the upper end openings of the respective upper intermediate booms 14. Is inserted so that it can expand and contract along its length. A connecting piece 18 is fixed to the upper end of the upper boom 15, and the connecting piece 18 is rotatably connected to a fixed piece 19 fixed to the front and rear of the lower surface of the lifting table 5 by a pin.
The distance between the fixing pieces 17 and 17 and the distance between the fixing pieces 19 and 19 are set to the same length, and when the telescopic booms 10 rotate and extend to form an X-shape, respectively. The elevating table 5 can be raised while maintaining the vehicle body 1 and the elevating table 5 in parallel.

An operating mechanism 20 for extending and retracting the entire lifting mechanism 4 is attached between the fixed piece 17 and the intermediate boom 12. The operating mechanism 20 is composed of a hydraulic cylinder and a guide mechanism. The structure of will be described in detail later.

Next, FIG. 4, FIG. 5, FIG. 6, FIG. 7 and FIG. 8 will explain in detail the internal structure of the elevating mechanism 4, that is, the telescopic boom body 10, and the combination thereof.

Each of the central booms 11, the lower middle booms 12, the lower booms 13, the upper middle booms 14, and the upper booms 15 that constitute the telescopic boom body 10
Each has a slender shape in which a thin steel plate is bent and the inside has a hollow cross-section that is slightly square.The center boom 11 has a cross-section that is slightly enlarged in the lateral direction. A partition plate 25, which divides the interior into two spaces along its length, is fixed. The lower intermediate boom 12 is inserted into one of the spaces of the central boom 11 divided by the partition plate 25, and the lower intermediate boom 12 has a slightly hollow cross-sectional internal hollow structure. There is. The lower boom 13 is inserted inside the lower intermediate boom 12, and the cross section of the lower boom 13 has a hollow inner shape that is slightly square-shaped. Also,
An upper intermediate boom 14 is inserted in the other space, which is an internal space of the central boom 11 and is partitioned by a partition plate 25, and the upper intermediate boom 14 has a slightly R-shaped cross section and has an internal structure. It is hollow. The upper boom 15 is inserted inside the upper intermediate boom 14, and the upper boom 15
The cross-sectional shape is slightly square and the inside is hollow.

The telescopic boom bodies 10 assembled in this way are horizontally arranged so that they are parallel to each other, as shown in FIG. In this figure, four telescopic boom bodies 10 are arranged side by side, but a space is provided between the insides of the central booms 11-B and 11-C.
A pipe-shaped kick receiver 26 is interposed between the centers of the kick receiver 26 and the kick receiver 26 so as to come into contact with the upper end of the kick mechanism 7. Central boom 11-B, 11
Reinforcing rods 27 and 28 are respectively interposed between the upper and lower ends of -C, and the center booms 11-B and 11-C and the kick receiver 2 are provided.
6. Reinforcing rods 27 and 28 form a ladder-shaped structure.

A bearing mechanism 29 for freely rotating the central booms 11-A and 11-B is interposed between the centers of the central booms 11-A and 11-B. The central booms 11-A and 11-B can rotate alternately. Similarly, the central booms 11-C and 11-D are rotatably connected to each other by the bearing mechanism 29.

Further, a reinforcing rod 30 is interposed between the lower intermediate booms 12 that extend and contract from the lower end openings of the central booms 11-B and 11-C, and from the upper end openings of the central booms 11-B and 11-C. A reinforcing rod 31 is interposed between the pair of upper and lower booms 14 that expand and contract, and the reinforcing rods 30 and 31 serve to lower the intermediate boom.
12 and the upper intermediate boom 14 can be slid in synchronization with each other. Further, between the central booms 11-A and 11-D arranged on both sides of the four telescopic boom bodies 10, the lower parts of the central booms 11-B and 11-C are dipped. Then, the reinforcing rod 32 is connected. In addition, the central boom
Between the upper ends of 11-A and 11-D, center booms 11-B and 11-
The reinforcing rod 33 is connected so as to straddle the upper side of C.
Therefore, the central booms 11-A and 11-D are assembled in a ladder shape with the reinforcing rods 32 and 33 interposed at both ends thereof, and the whole of the central booms 11-A, 11-D and the reinforcing rods 32 and 33 are assembled. It has a rigid structure. Next, the central boom 11-A, 11-D
The middle boom 11-
A reinforcing rod 34 is interposed so as to go under the B and 11-C to reinforce both lower intermediate booms 12.
In addition, a reinforcing rod 35 is interposed between the upper intermediate booms 14 extending and contracting from the central booms 11-A and 11-D so as to straddle the lower sides of the central booms 11-B and 11-C. Both upper intermediate booms 14 are reinforced by the rods 35. The seventh
The drawing is a cross-sectional view taken along the line XX in FIG. 6, showing the relationship between the central booms 11-A, 11-B, 11-C, 11-D and the bearing mechanism 29.

Next, FIG. 8 is an exploded perspective view showing the structure of the bearing mechanism 29.

The bearing mechanism 29 is capable of rotating the two central booms 11-A and 11-B with respect to each other.
A ring-shaped bearing washer 40 is closely attached to the outer surface of -B, and a circular guide groove is provided on the inner peripheral wall of the bearing washer 40.
41 is formed, and a screw hole is formed around the bearing washer 40.
42 is opened. The bearing washer 40 is arranged so that its central axis is on the same axis as the kick receiver 26 and is brought into close contact with the side surface of the central boom 11-B, and the screw 43 is inserted into the screw hole 42 to screw the screw. It has been stopped.

A ring-shaped seat plate 44 is fixed to the center of the inner surface of the central boom 11-A, and a screw hole 45 is opened around the seat plate 44. Guide groove 41
The sliding claws 46 that are engaged with the sliding claws 46 are brought into close contact with each other, and each sliding claw 46 is fixed to the seat plate 44 by a screw 47. The sliding claw 46 is fitted on the peripheral wall of the guide groove 41, and then the screw 47
Both are assembled so that they can rotate relative to each other because they are fixed by.

Next, FIG. 9 shows the central boom of the telescopic boom unit 10.
Lower middle boom 12, lower boom 13, upper middle boom
14 shows a mechanism for synchronizing each of the upper boom 15 and the upper boom 15.

In this embodiment, the lower intermediate boom 12 that extends and contracts from the central boom 11
And the amount of expansion and contraction of the upper intermediate boom 14 must be the same, and the amount of expansion and contraction of the lower boom 13 extending from the lower intermediate boom 12 and the upper boom 15 extending from the upper intermediate boom 14 must be the same. That is, as shown in FIG. 3, this is an indispensable condition for vertically raising the elevating table 5 while maintaining it horizontally. In FIG. 9, one of the four telescopic boom units 10 is explained, and the same synchronizing mechanism is adopted for the structure of the other three telescopic boom units 10. There is. Further, FIG. 9 is shown to explain this synchronization mechanism, and note that the positional relationship between the lower boom 13 and the upper boom 15 is slightly different from the actual mechanism in the arrangement of each member. I want to be done.

Inside the upper part of the central boom 11, a pulley 50 is rotatably supported so as to be slightly horizontal, and a wire 51 for synchronization is wound around the pulley 50. One end of the wire 51 Is connected to the upper end of the lower intermediate boom 12, and the lower end of the wire 51 is connected to the lower end of the upper intermediate boom 14. This allows the lower middle boom 12 and the upper middle boom to
The body 14 and the central boom 11 will move with the same amount of expansion and contraction. A pulley 52 is rotatably supported on the upper end side surface of the lower intermediate boom 12, and the pulley 52 is
A wire 53 is wound around 52, and this wire 53
One end of is connected to the upper end of the lower boom 13 and the wire 53
The other end of is connected to the lower end of the central boom 11. further,
A pulley 54 is pivotally supported on the upper end side surface of the upper intermediate boom 14, and a wire 55 is wound around the pulley 54.
One end of the wire 55 is connected to the upper end of the central boom 11, and the other end of the wire 55 is connected to the lower end of the upper boom 15.

Then, FIG. 10 illustrates the structure of the actuating mechanism 20 in the present embodiment in detail. This actuating mechanism 20 is attached to each of the four telescopic boom bodies 10, but one of them is explained in FIG. 10, and the actuating mechanism 20 attached to another telescopic boom body 10 is All have the same configuration.

A pair of guide rails 60 are fixed to the lower surface of the central boom 11 along the length direction thereof at intervals, and both guide rails 60 each have a U-shaped cross section. The guide rails are located so that the internal spaces face each other, and extend over almost the entire length of the central boom 11.
60 is stuck. A roller 61 is movably inserted in the inner space of the guide rail 60, and the roller 61 is axially supported by a bearing plate 62. The bearing plate 62 is held in parallel with the central boom 11. It is fixed to the bar 63. The operating rod 63 has its lower end connected and fixed to the upper end of the guide body 64. The guide body 64 is formed in a U-shape as a whole, and an elongated space is formed inside the two members facing each other. Are linked to.

In this way, the guide body 64 and the operating rod 63 are attached to the lower intermediate boom 12
At the same time, it moves with respect to the central boom 11. The guide body 64 is formed in a U-shape as described above, and the guide groove 65 having a U-shaped cross section is formed on each of the inner surfaces facing each other, and the inside of the guide groove 65 is formed. Each roller 66 is inserted movably,
The roller 66 is supported by a shaft 67. The shaft 67 is pivotally supported by a pair of support plates 68, and a pulley 69 is pivotally supported between the support plates 68. This support plate 68 is fixed to the tip of the cylinder rod 72,
A hydraulic cylinder 71 for operating the cylinder rod 70 is located in the internal space of the guide body 64. The base of this hydraulic cylinder 71 is the fixed piece 17
And are rotatably connected by a pin. A wire 66 is wound around the pulley 69. One end of the wire 66 is connected to the lower end of the lower intermediate boom 12, and the other end of the wire 66 is connected to the upper end of the hydraulic cylinder 71.

Next, FIG. 11 illustrates the structure of the kick mechanism 7 in detail.

The kick mechanism 7 includes a plurality of cylinder rods 75, 76,
It is a hydraulic cylinder that combines 77 in the shape of a bamboo and expands and contracts in three stages. At the upper end of the cylinder rod 77, a kick body 78 that is opened in a V shape upward is fixed. The kick body 78 comes into contact with the outer circumference of the kick receiver 26 and can lift the kick receiver 26, and the kick body 78 has a V-shaped bottom portion at the outer circumference of the kick receiver 26. A limit switch 79 for contacting with and detecting its position is fixed.

Next, FIG. 12 shows a part of the hydraulic control circuit in this embodiment. In this embodiment, only the circuit portion for lifting the lifting table 5 is described.

A suction side of a hydraulic pump 81 driven by the engine 80 is connected to an oil tank 82 that stores pressure oil. Electromagnetic valves 83 and 84 are connected to the discharge side of the hydraulic pump 81, and at the same time, return oil passages of these electromagnetic valves 83 and 84 are connected to an oil tank 82. And this solenoid valve 83
Is connected to the hydraulic cylinders 71-A and 71-B in series, and the solenoid valve 84 is connected to the kick mechanism 7. These two solenoid valves 83, 84 can be switched to neutral, tangent, and reverse connection, respectively.
Are provided with coils K and L, and the solenoid valve 84 is provided with coils M and N.

Next, FIG. 13 shows an electric control circuit in this embodiment.

A control device (not shown) is attached to the elevating table 5, and this control device is provided with a control switch 86 for raising and lowering the elevating table when operated by an operator. The control switch 86 has a contact 87 for controlling the ascending operation and a contact 88 for controlling the descending operation.The contact 87 is connected to the relay 89 and the contact 88 is connected to the relay 90. ing. The coil K is connected in series to the normally open contact 91 controlled by the relay 89, and the coil L is connected in series to the normally open contact 92 controlled by the relay 90. Further, the limit switch 79 is opened when it is not in contact with the kick receiver 26, and the normally open contact 93 and the coil M which are closed by the relay 89 are connected in series to the limit switch 79. . In addition, the limit switch
A normally open contact 94 closed by a coil 90 and a coil N are connected in series to 79.

Next, the operation of this embodiment will be described.

By operating the engine 80 attached to the vehicle body 1, and by making the hydraulic pop 81 follow by this engine 80,
The hydraulic pump 81 sucks up the pressure oil from the oil tank 82 and supplies it to the solenoid valves 83 and 84. By this operation, the aerial work vehicle stands by for the control of each part.

[Lift of the lift]

The state where the lift 5 is lowered to the lowest position is the state shown in FIGS. 1 and 2. A case where the lifting platform 5 is lifted from the lowermost position will be described. In this state, the kick receiver 26 is in contact with the kick body 78, and the limit switch 79 is in contact with the outer periphery of the kick receiver 26, so the limit switch 79 is closed.

In this state, operate the control switch 86 to raise the contact.
When 87 is closed, the relay 89 operates to close the normally open contacts 91, 93. Then, currents flow through the coils K and M, respectively, and the solenoid valves 83 and 84 are connected in the forward direction. Therefore, four hydraulic cylinders 71-A, 71-B, 71-C, 71-
The hydraulic pressure is supplied to each D, and the kick mechanism 7
Is also supplied with hydraulic pressure. Then, each hydraulic cylinder 71 extends in the length direction thereof and acts to push out each boom in the telescopic boom body 10. However, when the lifting platform 5 is at the lowest position (state shown in FIG. 1), the booms are oriented in parallel and in a straight line direction, and the direction in which the boom rotates about the bearing mechanism 29 in the X shape is a component force. Does not occur, and the lift 5 does not rise. However, since the hydraulic pressure is also supplied to the kick mechanism 7 from the solenoid valve 84 at the same time, the cylinder rods 75, 76, 77 of the kick mechanism 7 extend upward, and the kick body 78 pushes the kick receiver 26 upward. . Therefore, the central boom bodies 11-A, 71-B, 71-C,
71-D will be lifted so that it will be slightly X-shaped with the bearing mechanism 29 at the center.

When the telescopic boom body 10 is lifted by the kick mechanism 7 to be in a slightly X-shaped state, the operation of each hydraulic cylinder 71 is started. First, when the hydraulic cylinder 71 is operated and the cylinder rod 70 is pushed out, the pulley 69 is pushed out upward together with the support plate 68, so that the wire 66 is pulled up. Since one end of the wire 66 is connected to the upper end of the hydraulic cylinder 71, this position does not change, and the wire 69 is pushed out by pushing out the pulley 69.
Operates so that the lower intermediate boom 12 can be lifted. Therefore, each intermediate boom 12 begins to extend so that the lower boom 13 is pulled out from the lower end thereof.

At this time, the guide body 64 together with the actuating rod 63 moves the lower intermediate boom 12
However, the distance between the guide body 64 and the central boom 11 will change. However, since the tip of the operating rod 63 moves in the guide rail 60 by the roller 61, the operating rod 63 and the guide body 64 are kept parallel to the lower intermediate boom 12, while the hydraulic cylinder 17 is kept parallel to the lower intermediate boom 12. It helps to maintain and move so that.

In this way, the lower intermediate boom 12 is pushed up by the hydraulic cylinder 71, and the lower boom 13 is pulled out from the lower end of the lower intermediate boom 12, whereby the respective parts of the telescopic boom body 10 are interlocked. This interlocking operation will be described with reference to FIG. 9. When the lower intermediate boom 12 is pushed up, the lower boom 13 is pulled out from the lower end of the lower intermediate boom 12, and a pulley 52 is pivotally supported at the upper end of the lower intermediate boom 12. Therefore, the position of the lower boom 13 does not change, while the pulley 52 moves up, the wire 53 is pulled up, and the central boom 11 is moved with respect to the lower intermediate boom 12. The distance that the central boom 11 moves with respect to the lower intermediate boom 12 is set to the same length as the length by which the lower boom 13 is pulled out from the lower intermediate boom 12. Therefore, when viewed from the central boom 11, the lower middle boom 12 and the lower boom 13 are relatively pulled out by the same length. When the lower intermediate boom 12 is pulled out from the central boom 11, the wire 51 is pulled out downward, the pulling out of the wire 51 is transmitted to the upper intermediate boom 14 via the pulley 50, and the upper intermediate boom 14 is placed at the upper end of the central boom 11. It will be pulled out from the opening. The upper middle boom 14 is the central boom.
The amount withdrawn with respect to 11 is the same as the amount with which the lower intermediate boom 12 is withdrawn from the central boom 11. When the upper intermediate boom 14 is further pulled out from the central boom 11, the pulley 54 axially supported by the upper intermediate boom 14 pulls up the wire 55. Since one side of this wire 55 is fixed to the central boom 11, this position does not change, and the upper boom 15 connected to the other end of the wire 55 does not move.
Will be drawn more. The amount of the upper boom 15 pulled out from the upper intermediate boom 14 is the same as the amount of the upper intermediate boom 14 pulled out from the central boom 11.

In this way, the wires 51, 53, 55 are interlocked with each other, and the lower middle boom 12, the lower boom 13, the upper middle boom 14, and the upper boom 15 are interlocked with respect to the central boom 11, and are drawn out. The amount by which the lower intermediate boom 12 and the upper intermediate boom 14 are pulled out with respect to the central boom 11 is the same, and the amount by which the lower boom 13 is pulled out by the lower intermediate boom 12 and the upper boom 15 by respect to the upper intermediate boom 14 are the same. The amount of pull-out is also the same, and the booms are synchronized with the same amount of movement.

This interlocking operation is performed by one telescopic boom body shown in FIG.
10 synchronization is described, but other telescopic boom bodies 10
The same synchronization operation can be performed for the same. Then, all the booms of the telescopic boom bodies 10 formed in the X-shape have the same movement amount, and the elevating mechanism 4 greatly expands while maintaining the X-shape and making the upper and lower shapes similar to each other intermittently. It will be. For this reason, the lift 5 is mounted on the vehicle body 1
Is lifted vertically upwards with respect to the lift table 5
Will be kept horizontal.

By this series of operations, by operating the hydraulic cylinder 71 to extend each boom of the telescopic boom body 10,
The aerial work vehicle can be changed from the state shown in FIG. 1 to the state shown in FIG. 3 and the lifting platform can be lifted up to a higher position, and the total length of the telescopic boom body 10 is about 10% smaller than that when it is contracted. It can be made 5 times longer. And
If the lift table 5 is lifted to a predetermined position, and if the hydraulic pressure supplied to the hydraulic cylinder 71 is stopped at that position, the lift table 5 will be held at that height position, and work at a high place must be performed. You can

In the extension operation of the pair of telescopic boom bodies 10, two central booms 11-A and 11-B and central booms 11-C and 11-D are used.
Will rotate relative to the
Done by 29. In this bearing mechanism 29, since the sliding claw 46 is engaged with the guide groove 41 of the bearing washer 40, the sliding claw 46 moves while sliding on the inner circumference of the guide groove 41.
Therefore, the central booms 11-A and 11-B can be relatively rotated in the opposite directions without changing the left and right intervals, and both can be maintained in the X shape.

Then, as the bearing mechanism 29 is lifted by the hydraulic cylinders 71, the kick receiver 26 is lifted by itself, is separated from the upper surface of the kick body 78, and the limit switch 79 is opened. Therefore, no current flows through the coil M, and the solenoid valve 84 is in a neutral state. After that, both the lift table 5 and the bearing mechanism 29 continue to move up as described above, but the kick mechanism 7
Each of the cylinder rods 75, 76, and 77 of FIG.

[When lowering the platform]

As described above, it is necessary for the worker to lower the elevating table 5 after elevating the elevating table 5 to the high position shown in FIGS. 1 to 3. The operation in this case will be described.

First, a worker on the lift 5 closes the contact 88 of the control switch 86. Then, a current flows through the relay 90 and the normally open contacts 92, 94 are closed. Therefore, the current flows through the coil L, but the current does not flow through the coil N because the limit switch 79 is opened. When a current flows through this coil L, only the solenoid valve 83 is connected in the opposite direction,
The pressure oil from the hydraulic pump 81 is supplied to each hydraulic cylinder 71 in the reverse direction. Therefore, the length of each hydraulic cylinder 71 is reduced, and the cylinder rod operates so as to be drawn inward of the hydraulic cylinder 71. Then, contrary to the above, the intermediate boom 12 and the upper intermediate boom 14 slide toward the inside of the central boom 11, and the lower boom 13 slides toward the inside of the lower intermediate boom 12 and the inside of the upper intermediate boom 14. The upper boom 15 slides toward and the total length of the telescopic boom 10 is reduced. This operation is the opposite of the above, and the lift 5 is gradually lowered.

Then, the central boom 11 is axially supported by the bearing mechanism 29 so as to always have an X-shape, and descends while rotating around the bearing mechanism 29. When the kick receiver 26 of the bearing mechanism 29 descends and contacts the kick body 78, the kick receiver 26 is supported by the kick body 78. At the same time, the limit switch 79 contacts the kick receiver 26, and the limit switch 79
Normally closed contacts that have already been closed.
A current will flow through the coil N via 94. From this, the solenoid valve 84 is connected in the opposite direction by the coil N,
The kick mechanism 7 is supplied with reverse hydraulic pressure from the hydraulic pump 81.

Then, the kick body 78 comes into contact with the kick receiver 26, and the lift table 5
The load is gradually supported while being supported by the kick body 78. That is, the load from the lift table 5 has been received by the hydraulic cylinders 71 until now, but the kick body 78 receives a part of the load by the reverse connection of the solenoid valve 84, and the kick mechanism 77 gradually shrinks. It will support a part of the load. This means that each hydraulic cylinder
With the kick mechanism 7 supporting part of the load supported by 71,
The pulling force of the wires 53, 55 actuated by the hydraulic cylinder 71 is reduced. For this reason, the inclination angle of the central boom 11 with respect to the vehicle body 1 becomes shallow, and even if the component force of the load applied from the elevator 5 increases, the component force from the elevator 5 dispersed by the wires 53 and 55 does not increase. .

Next, another embodiment of the present invention will be described.

In this embodiment, a part of the hydraulic control circuit and the electric control circuit are modified, and the same parts as those in the first embodiment are designated by the same reference numerals and their description is omitted.

FIG. 14 shows a hydraulic control circuit of another embodiment.

Throttle valves 95 and 96 are interposed between the solenoid valve 83 and the hydraulic cylinders 71-A and 71-B, respectively. And
Electromagnetic valves 97 and 98 for disconnecting the hydraulic circuit are connected in parallel on both sides of each throttle valve 95 and 96. The solenoid valve 97 is provided with a coil Q for disconnecting the oil passage, and the solenoid valve 98 is connected with a coil R for disconnecting the oil passage.

Next, FIG. 15 shows an electric control circuit of another embodiment, in which coils Q and R are connected in parallel with the coil N, respectively.

When the lift table 5 can be lifted in this embodiment, it can be started by closing the contact 87 of the control switch 86 as in the first embodiment. When the contact 87 is closed, the relay 89 is activated, the normally open contacts 91 and 93 are closed, current flows through the coils K and M, the solenoid valves 83 and 84 are connected to the positive side, the kick mechanism 7, the hydraulic cylinder. Pressure oil is supplied to 71, and the lifting platform 5 is raised. The subsequent operation is the same as in the first embodiment.

However, when the lift table 5 is lowered, the operation is slightly different from that of the first embodiment.

That is, since the limit switch 79 is open in the state where the lift table 5 is in a high position before the kick receiver 26 contacts the kick body 78, the lift table 5 is lowered by the reduction amount of the hydraulic cylinder 71. When the kick receiver 26 comes into contact with the kick body 78 due to the lowering of the lift 5 and the bearing mechanism 29, the limit switch 79 closes, and the normally open contact 94 already closed by the relay 90 causes the limit switch 79 to close. Current flows through the coils N, Q, and R. Then, the solenoid valve 84
Reversely contact each other and apply pressure oil from the hydraulic pump 81 to the kick mechanism 7 in the opposite direction to cause the cylinder rods 75, 7 of the kick mechanism 7 to move.
Gradually lower 6, 77. By this operation, the kick body 78 is gradually lowered while supporting the load from the kick receiver 26.

At this time, since currents flow through the coils Q and R at the same time, the solenoid valves 97 and 98 are closed, and the solenoid valve 83 and the hydraulic cylinder 71-A,
71-B direct connection goes down. Therefore, the reverse hydraulic pressure is supplied to the hydraulic cylinders 71-A and 71-B through the throttle valves 95 and 96 at a low speed to the hydraulic cylinders 71-A and 71-B. Therefore, the hydraulic cylinders 71-A and 71-B contract at a slow speed, and the lowering speed of the kick mechanism 7 becomes faster,
It follows the operation of the kick mechanism 7.

Therefore, the wires 53 and 55 pulled by the respective hydraulic cylinders 71 are always in a state in which a pulling force is applied, and the wires 53 and 55 follow the kick mechanism 7 while having a certain pulling force. In this operation, unlike the first embodiment, the hydraulic valves 71-A and 71-B are directly connected to the solenoid valve 83 to continue the reduction operation, and the reduction speed of the hydraulic cylinder 71 is lower than the reduction speed of the kick mechanism 7. If there is a phenomenon that the wire speed becomes faster, the wires 53 and 55 are loosened, and the wires 53 and 55 hang down inside the telescopic boom body 10. Due to the looseness of the wires 53, 55, it is possible to prevent the phenomenon that the wires 53, 55 fall off the pulleys 50, 52, 54, 69 that are being wound around and the lifting operation cannot be performed again.

In this embodiment, in order to lift the lifting platform 5, the lower middle boom 12 and the lower boom 1 are different from the central boom 11.
3, the lower intermediate boom 14 and the upper boom 15 are slidably inserted, respectively, and described by the structure of the telescopic boom body 10 that expands and contracts in five steps, but is not limited to this embodiment.
Needless to say, a telescopic boom body that expands and contracts in three stages, in which the lower boom and the upper boom can be expanded and contracted relative to the central boom 11, has the same effect.

〔The invention's effect〕

Since the present invention is configured as described above, conventionally, when lowering the lifting platform, it was lowered by the contracting force of the hydraulic cylinder provided in the telescopic boom body. It can bear the load of the table. As a result, even if the tilting angle of the telescopic boom body becomes shallow and the component force of the load from the lifting platform becomes large, most of the component force is supported by the kick mechanism, and the upper boom provided in the telescopic boom body is supported. It is possible to prevent a large load from being applied to the wires, chains, etc. used to synchronize the lower boom with the lower boom.

For this reason, it is possible to prevent breakage accidents such as wire breakage, and it is possible to suppress the safety factor of the wire and the chain to a low level, so that it is possible to reduce the weight of the entire device.

[Brief description of drawings]

FIG. 1 is a side view showing a state in which the lifting platform of an aerial work vehicle according to an embodiment of the present invention is lowered to the lowest position, FIG. 2 is a front view of the same as above, and FIG. FIG. 4 is a side view showing a state of being raised to a height position, FIG. 4 is a perspective view showing an outline of a telescopic mechanism, and FIG. 5 is a sectional view showing a structure of a central boom.
FIG. 7 is a plan view showing the arrangement of the central booms in the lifting mechanism, FIG. 7 is a sectional view taken along line XX in FIG. 6, and FIG.
FIG. 9 is an exploded perspective view showing the structure of the bearing mechanism, FIG. 9 is an explanatory view showing the synchronizing mechanism of the telescopic boom body, FIG. 10 is a partially sectional perspective view showing the structure of the operating mechanism, and FIG. FIG. 12 is an enlarged perspective view showing the relationship between the kick mechanism and the kick receiver of the embodiment, FIG. 12 is a hydraulic control circuit of the expansion mechanism, FIG. 13 is an electric circuit diagram for controlling the solenoid valve of the hydraulic circuit, and FIG. 14 is this book. FIG. 15 is a hydraulic circuit diagram showing another embodiment of the invention, and FIG. 15 is an electric circuit diagram for controlling an electromagnetic valve of a hydraulic circuit in another embodiment of the invention. 1 ... Car body, 4 ... Lifting mechanism, 5 ... Lifting platform, 7 ... Kick mechanism, 10 ... Telescopic boom unit, 11 ... Central boom, 12
...... Lower middle boom, 13 ...... Lower boom, 14 ...... Upper middle boom, 15 ...... Upper boom, 26 ...... Kick receiver, 78 ...... Kick body, 79 ...... Limit switch, 83, 84 ...... Solenoid valve .

Claims (1)

[Claims] 1. A movable vehicle body, a lift table located above the vehicle body and capable of moving up and down, a pair of middle booms pivotally supported in an X shape so as to be rotatable in the center, and the length of each middle boom. The lower booms that are moved in the vertical direction and whose lower ends are connected to the vehicle body, and the upper booms that are moved in the longitudinal direction of each middle boom and whose upper ends are connected to the lifting platform, and the upper vehicle body. It consists of a kick mechanism that is fixed to the upper part of both middle booms and pushes up the center of both middle booms, and a detection means that detects that both of these middle booms and kick mechanism contact each other. A kick mechanism for an aerial work vehicle characterized by lowering the load of the middle boom while supporting the load of the middle boom by the kick mechanism after detecting the contact with the detecting means.